An abyssal plain is an underwater plain on the deep ocean floor, usually found at depths between 3000 and 6000 m. Lying generally between the foot of a continental rise and a mid-ocean ridge, abyssal plains cover more than 50% of the Earth âs surface. They are among the flattest, smoothest and least explored regions on Earth.
Jim Beckwourth. On this day in 1844, Jim Beckwourth discovered a path through the Sierra Nevada Mountains that now bear his name. Beckwourth Pass on U.S. Alt 40 between Reno, Nevada and Sacramento, California made overland travel to the gold fields of California. Tweet.
His published writings were also instrumental in the creation of Grand Canyon and Sequoia national parks. At the end of his life, Muir and the Sierra Club fought a bitter and ultimately unsuccessful crusade against construction of the OâShaughnessy Dam in the Hetch Hetchy Valley in Yosemite National Park. This was reportedly the first major battle of the environmental movement.